'use strict';

let watermark = {};

let setWatermark = (str) => {
    let id = '1.23452384164.123412415';

    if (document.getElementById(id) !== null) {
        document.body.removeChild(document.getElementById(id));
    }

    let can = document.createElement('canvas');
    can.width = 160;
    can.height = 120;

    let cans = can.getContext('2d');
    cans.rotate(-20 * Math.PI / 180);
    cans.font = '16px Vedana';
    cans.fillStyle = '#bfbfbf';
    cans.textAlign = 'left';
    cans.textBaseline = 'Middle';
    cans.fillText(str, can.width / 4, can.height / 2);

    let div = document.createElement('div');
    div.id = id;
    div.style.pointerEvents = 'none';
    div.style.top = '70px';
    div.style.left = '0px';
    div.style.position = 'fixed';
    div.style.zIndex = '100000';
    div.style.opacity = 0.5; // 调节字体颜色的深浅
    div.style.width = document.documentElement.clientWidth - 10 + 'px';
    div.style.height = document.documentElement.clientHeight - 100 + 'px';
    div.className = 'water-turn';
    div.style.background = 'url(' + can.toDataURL('image/png') + ') left top repeat';
    document.body.appendChild(div);
    return id;
};

// 该方法只允许调用一次
watermark.set = (str) => {
    let id = setWatermark(str);
    setInterval(() => {
        if (document.getElementById(id) === null) {
            id = setWatermark(str);
        }
    }, 500);
    window.onresize = () => {
        setWatermark(str);
    };
};
const outWatermark = (id) => {
    if (document.getElementById(id) !== null) {
        const div = document.getElementById(id);
        div.style.display = 'none';
    }
};

watermark.out = () => {
    const str = '1.23452384164.123412415';
    outWatermark(str);
};
export default watermark;
